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Bought this new early in 1990 and it has been in use ever since, but generally light use and with relatives. I will get it at least yearly and 'fix it up' again, but it is still original - the engine has never had any internal repair, not even a new carb or gas tank. The major problem at this point is the blades are obsolete. I have to get a generic 20" blade and adapt it - this is getting old. There are two reasons for needing a special blade or adapting one - the deck has a round 'plenum' that is meant to isolate the rotating air and increase the effectiveness of bagging/discharging - no mulching really possible, and it is the sweetest little bagger I have ever seen - manicures the lawn. Anyway, the plenum wall comes down so far a straight blade will scrape it. so, the original blade has a 'dip' on each side to clear the wall. Also, the blade adapter has locating pins for the blade but they are closer together than the slots for them in any generic blade. I found that using a 20" mulching blade that angles slightly down on each side clears the plenum wall, but I have to take the Dremel and round file to the slots to extend them toward the center. The center hole is large because its a generic, so this really doesn't leave much steel between the extended slots and the hole, which has a filler plug. Mounting the blade is somewhat tedious because of the loose fit from all this hand work, trying to get it centered - not the best solution. I tried to find an old-style blade adapter that would work with it to no avail.
Since my SIL has it now and is not known for taking care of things, every year I figure is going to be its last, but it just keeps working. Doesn't use oil and doesn't smoke. Never had to put a lower seal in it (yet). It has the 3.5 HP B&S but it is a premium version with quiet muffler - that's still original too. I have replaced the wheels, grass bag and starter cord. They called me once and said it was 'squealing'
so I went over there expecting to see a rod through the block but it turned out to be the starter clutch - all I did was lube it but when you have a really old mower, funny things begin to happen that you may not have had trouble with before.
I'm afraid it doesn't look this sharp anymore but it is still out there cutting grass. The blade shown is the last original one I could find, about 15 years ago.

Don't build them like that anymore. I'd hate that dogleg handle though. Does that motor have an unusual bottom shaft length? A standard blade adapter should fit and work with a single center bolt and most replacement blades that would clear the shallow deck. Good looking mower!

This is weird; I made the post Friday, and Saturday I found out they bought a new mower after 'having trouble' with the old HJ. So I went by and picked it up today, expecting that the 30-year saga of this mower was in it's last chapter. Got home with it and started checking it out - everything seemed okay - no oil use in two years and it finally had gotten dark enough to see it on the stick (Castrol 'Edge' synthetic 10W-30). I pulled the starter cord and it fired right up. Turned it off, set the wheels at 3" and mowed a few minutes, discharging. No problem. Put the bag on and did the whole front yard - man, this thing is still the sweetest bagger I've had, and again, no problems. I guess they just wanted a new mower, and since they tend to let the grass get too tall and cut it too short, probably they will need the 6 HP mower.
So, here it is - I didn't even wash it for the picture - this is what it really looks like now, and actually not too bad for 30 years of service. Let's just say I cringe when I read the tales of guys never changing the mower's oil. One of my many faults is changing oil more than I really have to, on everything - but everything tends to run forever.

tom3 said:

Don't build them like that anymore. I'd hate that dogleg handle though. Does that motor have an unusual bottom shaft length? A standard blade adapter should fit and work with a single center bolt and most replacement blades that would clear the shallow deck. Good looking mower!

Click to expand...

The blade adapters changed in 1994. A post-'94 won't fit, and nobody makes one that has the wider-spaced pins AND that will fit. I forget the details but it seems like the new kind won't fit over the Woodruff key. Also many replacement blades will not clear the plenum so its trial and error there.
I don't know what you mean by 'dogleg' handle - possibly how it attaches at the bottom? It doesn't affect anything.
Anyway, I decided to keep it a little while even though my shed is pretty crowded at the moment. I'll have to do some serious shed-cleaning to get it in there so I don't have to move it to get the regular mowers.

Hello,

Those are sweet mowers (I look for the very rare 2 cycle engine option). I have a machine shop in my basement and could make the blade/blade adapter fit.

Regards

Jeff

What did the 2-cycle have on it, a West Bend?

Unless the crankshaft is tapered or a funny size then any blade adapter ( we call them carriers ) should fit .
The crank will be 7/8" or 1" if it was a USA model or 20 mm or 25 mm if it was an export model .
So start by getting the carrier off the crank shaft.
This will not be easy if it has not been pulled regularly and the shaft greased to prevent it rusting on.
Once you know what you are looking for there will be aftermarket carriers that will fit
Honda for metric and any USA brand for imperial
Steel ones will have the blade closer to the end of the crankshaft and aluminium ones will be further away but we are talking 1/4" so it should not make any difference to the machine in use.

Hello,

Not a West Bend, but a Briggs and Stratton 2 cycle, same engine used on certain John Deere (also rare) walk behinds. YouTube has some video's of these B&S 2 cycles.
The Komatsu Zenoah Venture – In May 1987, Briggs & Stratton entered into an agreement with yet another Japanese company, executing a 10-year contract with the Komatsu Zenoah Company of Tachikawa, Japan. Under the terms of the contract, Komatsu would manufacture a 2-cycle, 4 hp (3 kW) engine, in which Briggs & Stratton would purchase and distribute in the United States, Europe, Australia and New Zealand. Said Fred Stratton, "This venture was not successful, because the rising price of the yen made the engine too expensive in the U.S."

Consumer Reports listed the mower you have as a "Best Buy" out of all the mowers they tested.

Regards

Jeff

bertsmobile1 said:

Unless the crankshaft is tapered or a funny size then any blade adapter ( we call them carriers ) should fit .
The crank will be 7/8" or 1" if it was a USA model or 20 mm or 25 mm if it was an export model .
So start by getting the carrier off the crank shaft.
This will not be easy if it has not been pulled regularly and the shaft greased to prevent it rusting on.
Once you know what you are looking for there will be aftermarket carriers that will fit
Honda for metric and any USA brand for imperial
Steel ones will have the blade closer to the end of the crankshaft and aluminium ones will be further away but we are talking 1/4" so it should not make any difference to the machine in use.

Click to expand...

Sure, I removed the existing blade driver - it had never been off before but a little Kroil and a gear puller did the trick. I'm telling you the modern drivers do not work. Now I'm not a mechanic so I definitely don't know the good places to look but I do shop the major mower supply guys. They all seemed to have the same part, and that's where I found out about pre and post 1994. The crank is not weird in any way - just a straight shaft with a keyway just as you would expect. The problem is it was a couple years ago and I just don't remember everything that was wrong about the part but I do remember that I would have had to get a machinist to work on it in order to use it, and that's when I abandoned the idea.

Go to Stens, Rotary, Oregon & Prime Line.
Search their on line catalogue then check the details of each blade holder.
You might have to do multiple searches using adapter, holder , carrier , etc
Some have buil in keys & some have key slots
Measure your crankshaft
I seriously doubt that an off the shelf one from an other brand would not just slip on

Apart from the keyway & shaft size the only difference I have come across is the thickness from the end of the hole for the crankshaft & the flat surface the blade sits on which of course alters the blade height.
But as mentioned earlier it would only account for 1/4" max.

I keep onsaying this because itis the easiest way, find a repair- used mower only workshop and take your blade adapter to them.
Most of them will be like me & have a box full of them that were removed from deceased mowers before they were broken down for scrap.
New mower frnchise shops are mostly interested in selling you a new mower and in most cases the person behind the counter is a computer jockey & not a mower tech so they have no idea

I remembered the problem; the new-style driver has the key made into it so the crankshaft must have a keyway that starts at the bottom. The old way was the driver has a keyway in it that fits a separate key in the crank - the complete opposite. The crank has a short keyway for the Woodruff key but it doesn't extend anywhere near the end of the crank. So, there was no reasonable way to adapt the new blade driver to the old crank.
However, I like the idea of checking around for an old one that will take the new blades. I know of two places right away that have 'mower graveyards' behind the shop.

I'll just throw this out there. There have been a couple million mowers built with a single bolt mounted blade. I'd probably grind off those two outer knobs and go with a standard single bolt and heavy washer type blade mount if finding a workable blade is a problem. 3.5 horspower is not going to twist that blade off.

Grinding off the locating pins was one of my first thoughts, and I will definitely consider doing it when the time comes for another new blade and if I still have it. At this point I'd really like to find a good home for it.

I think this one's time is just about up. Engine is still good, deck is good, but the blade is obsolete, it needs another set of wheels and axles and the bag is wearing out. Plus the major factor is I just don't need it and I have no room for it.
Oh, BTW, the problem with the post-1994 blade drivers is they have a built-in key, which matches a shaft with a continuous slot, or 'keyway'. My driver has a built-in keyway to fit a shaft with a Woodruff key or perhaps a continuous key.
I probably won't be able to throw this mower away but I would gladly give it to someone who wanted it. Maybe I'll clean out my shed and keep it around a little longer as a very light and maneuverable trim mower.

I think I found an adapter that will work - just like the old one except the blade pins are farther apart (2") which will allow the use of a common 20" generic blade. Yes, it also appears to be thicker in the bottom surface (by the drawing provided) as you mentioned. I'll scribe in the deck where the current blade hits and see if I think I might have to set the deck height up a notch after checking where the new blade hits. Of course, the existing blade already would scribe lower than the original blade because of its design, so I'm probably looking at about a 1/2" total adjustment which is one notch. I just have to make sure the blade remains above the deck opening - if it doesn't this plan is toast.
Assuming the adapter fits, it really solved the problem, because now I can give/sell it to somebody who will use it without trying to tell them how to modify a blade to work, or just keep it around if I can make some room in the shed.

BTW, just looking at my picture above showing the last authentic blade I could get for it, you can see that the blade would scribe the deck probably about 5/8" up from the edge, so I'll use that as my desired value. Man, you never know how an old picture will come in handy some day.

Well, it worked! The adapter is taller than the old one but the new blade is straight instead of the previous generic blade that had 'drooping' ends. The result is the new blade scribes the deck about 1/4" above the lower edge which is good enough. It also clears that ring plenum under the deck which is another good thing. Very close tolerances on this deck - the original blade was designed to hug that plenum to get all of the vortex effect possible for efficient bagging. I probably have lost some of that efficiency but it basically works great, and now a blade swap is just that, not two hours over the vise modifying a blade that really doesn't fit.

After some careful measuring, the blade is about 1/4" lower than the marking on the wheel adjusters, so a setting of 3" is really 2 3/4". Consequently I set it at the next setting which is 'High', which will give about a 3 1/4" cut.

Interesting that your mower is pretty nearly the same as my T-20, which I've documented here along with several other Jakes... https://www.mylawnmowerforum.com/threads/jacobsen-push-lawn-mower-history-in-pictures.60705/

I think yours is maybe a year or two older - it has the Homelite/Jacobsen graphics (just like my 20" red mulcher) where mine indicates "Jacobsen - a division of Textron".

Older thread I know but here's my fleet of Jacobsen and HJ. After abusing the first one from the early eighties, I learned my lesson after buying first a new Craftsman (crapsman) that I returned after 1/2 mow, then a Honda SP that weighed a ton, lasted 6 yrs before it died. Found a Jacobsen on Kijiji, and my adventures in care and maintenance began, happily. What a mower! On these light machines the 3.5 Briggs easily outperforms the newer machine's 6 and 6.5 hp. Body parts are not so easy to find but it's unusual to need them. I've never lost a belt and cables can be made. The blade attachment pattern is tricky but a drill press helps in adapting 'generic' blades.